1. Field of the Invention
The present invention relates to a blade drive device and an optical apparatus.
2. Description of Related Art
There exists an optical apparatus such as a camera which includes a driving source such as a voice coil motor inside in related art. There is a driving source which generate a driving force by an electromagnetic force. The magnetic flux leaked from the driving source (hereinafter referred to as a “leakage flux”) may affect the operation of components inside the optical apparatus. For example, in JP-A-2008-250156 (Patent Document 1), there is disclosed a camera which includes an actuator means, a camera-shake correction optical means and a driving means for driving the camera-shake correction optical means to a prescribed position. The camera described in Patent Document 1 controls the driving means by a control means in accordance with the operation timing of the actuator means. Accordingly, the camera described in Patent Document 1 can eliminate the influence of vibration, magnetic induction and magnetic variation inside the actuator occurring when the actuator is driven, thereby realizing a camera-shake correction function not affected by noise or mechanical vibration.
Incidentally, a blade drive device can be mounted on a camera which is mounted on a cellular phone and so on in recent years for improving imaging performance. The blade drive device includes a lower plate having an opening formed around an optical axis of a lens, and an actuator opening and closing the opening of the lower plate by driving blades. The blade drive device is attached so as to overlap a camera module having the lens and a lens drive device.
However, as the above blade drive device is arranged close to the lens drive device, the operation of the actuator may be affected by the leakage flux leaked from the lens drive device. Specifically, defects such as variation in stop positions when the actuator is not energized and shortage of an energization torque occur in the actuator due to the leakage flux. As these defects of the actuator occurs by a stationary leakage flux, it is difficult to eliminate these defects by the control. Accordingly, operation failures may occur in the blade drive device in the case where it is difficult to drive the blades according to the specification, the case where abnormal exposure is caused and other cases. Therefore, there is room for improvement in the related-art blade drive device in a point that operation failures due to the leakage flux are suppressed.
In view of the above, an object of the present invention is to provide a blade drive device capable of suppressing operation failures due to the leakage flux and an optical apparatus including the blade drive device.